Concerning R1b-U152 I'm even wondering if it was so Celtic... It could have been the most frequent among Belgae and some of the Belgae seem having spoken a cousin dialect of Italo-Celtic origin, but closer to well formed Italic dialects than to Celtic ones. Belgae are supposed by some old scholars to be of E-Bavaria/Bohemia geographical origin. I don't know if this is very reliable but I have no recent clues? So more eastern La Tène descendants? Could it be possible that Celtic first arose rather among L21 bearers or L21 bearers ancestors? One of the languages identified (based on few and little it's true) in Rhaetia seems also of the same nature (Italo-Celtic towards Italic). I' don't speak of the Etruscanlike dialect here. A new thesis (not at hand, just other fora rumors)"says" Celtic was born in Central-Eastern France, not on the Atlantic shores, not in Southern Germany/Bohemia; La Tène archeological culture wouldn't be a critarium for language. According to it, Celtic dialects gained ground later eastwards and westards. Wait and see, so numerous new thesis arise these times.